Typical building practice requires construction of a footing or foundation upon which vertical concrete walls of a structure rest. A typical outer wall may range from 6-12 inches in thickness and the footing upon which the walls rest is typically wider than the wall width and may have a vertical depth (height) of 6-12 inches. Because these foundations are commonly a substantial distance below ground level, accumulation of water with a head of pressure at the footing level is a continuous risk. To prevent this ground water from entering the building through floor or foundation cracks, or through crevices between the foundation and basement floor, good building practice provides a means for removing the undesired ground water. Relatively standard procedures have developed over the years to construct sturdy footings/foundations and to provide a drainage system to remove future unwanted ground water.
The standard procedures include preparing a trench or excavation to the appropriate depth and dimensions to accommodate the footing/foundation forms and drainage system. Next, the inside and outside corner points of the footing/foundation wall are surveyed and a string or chalk line is placed around the intended footing/foundation perimeter. In the prior art, planks (typically 2.times.4-2.times.12-inch sections of seasoned wood) were arranged along the surveyed line and secured in place by common stakes. Because foundation forms are typically a pair of serpentuitous parallel walls, the prior art planks were cut to appropriate lengths using either mitered ends or special corner pieces to maintain the parallel relationship throughout the footing/foundation perimeters. After completing the entire footing/foundation network, concrete was poured between the forms, appropriately screeded, and allowed to set. When the concrete was sufficiently hard (typically the next day), the prior art forms were removed and a drainage system was installed thereafter.
A typical drainage system includes drain tiles having a plurality of apertures to allow water to enter the tiles. The prior art drain tiles were positioned adjacent the footing/foundation and were typically in fluid communication with either a sewer, a dry well, or a sump pump to remove the undesired ground water from around the footing/foundation. It was also customary to place gravel or filler stone around and over the drain tile to create a leach field thereby assisting water to flow into the drain tile.
The labor intensive nature of this prior art technique and the cost associated with purchasing form materials (planks/stakes) as well as drain tiles added significant expense to the typical construction project. Removing the form materials (planks/stakes) after sufficient hardening of the footing/foundation is a tedious practice. Installing an independent drainage system is also a costly and labor intensive procedure. Once the forms are removed, a certain amount of retrenching is required to assure proper positioning of the drain tiles adjacent the footing/foundation and at the appropriate depth within the excavation. If construction has started on the structure (as is typically the case), backfill and debris between the footing/foundation and the excavation walls will have undoubtedly accumulated. Removal of this backfill and debris requires hand shoveling, which escalates the prior art labor costs associated with laying the drainage systems. Moreover, due to the risk of injury, the Occupational Safety and Health Administration (OSHA) prohibits human activity within certain types/depths of trenches until the walls are shored. Thus, as well as introducing additional opportunity for injury, the costly prior art step of removing backfill and debris by hand shoveling may also violate OSHA regulations.
Moreover, the prior art drain tiles are typically laid directly on the excavation bottom with various tile apertures positioned in close proximity to the excavation bottom. Over time, silt and sediment tend to gravitate through the gravel leach field and accumulate on the excavation bottom adjacent the drain tiles which may block the tile apertures and hinder water drainage. Further, the close proximity of the tile apertures to the excavation bottom introduce the risk that silt or sediment will enter the drain tile and partially (or completely) clog the tile.
Recognizing the cost associated with the highly labor intensive prior art footing/foundation construction techniques (i.e. excavating, installing forms, pouring the footing, removing the forms, re-trenching, constructing the drainage system, laying a gravel leach field, and backfilling the excavation), attempts have been made to minimize these costs. Hreha, U.S. Pat. No. 3,613,323 and Parker, U.S. Pat. Nos. 5,120,162 and 5,224,799 each disclose foundation forms with integral drainage tiles or planks. The apparent purpose of the Hreha and Parker references is to eliminate the need for manually removing the forms after the footing/foundation is set and constructing an independent drainage system around the footing/foundation thereafter. While Hreha and Parker no longer require the entire drainage system to be separately constructed, these references require custom designed materials thereby offsetting the alleged labor savings with an increase in material costs. Parker ('162 and '799), for example, discloses custom designed planks having a precise horizontally symmetric shape and equally elaborate connectors to allow various serpentuitous patterns to be constructed. These stakes are also custom designed and molded. Moreover, as illustrated in FIGS. 3-4 of the '162 patent the Parker forms require separate solid planks in addition to the hollow foraminous standard planks to accommodate a footing/foundation of atypical depth (i.e. deeper than the height of a standard plank) thereby adding to the number and cost of materials which must be inventoried to use the Parker system. Similarly, Hreha discloses an elaborate multi-tiered form including drain tiles, mitered where appropriate, resting on the excavation bottom and a wall section positioned thereabove. The walls and tiles are both secured in position by stakes.
In addition to the material expense associated with the large inventory and custom molded drain tiles/planks, the drainage systems of both Hreha and Parker still require manual attention after the footing/foundation hardens. Similar to the prior art techniques discussed above, the wall sections and stakes of Hreha are manually removed after the concrete hardens. While the footing/foundation forms disclosed by Hreha and Parker are non-biodegradable and include an integral drain, a leach field is not created adjacent the drain tiles until after the footing/foundation concrete sets. Prematurely pouring the gravel and/or filler stone for the leach field may misalign the form which could affect the footing/foundation integrity. Therefore, contractors employing the Hreha or Parker techniques will typically wait a day or two after pouring the footing/foundation before pouring gravel therearound. Because construction sites are typically busy at this stage of the project, backfill and debris commonly accumulate in the excavation during this day or two day lag which demands an additional labor commitment to retrench the excavation prior to pouring the gravel or filler stone.
Further, as is typical with other prior art drainage systems, the Hreha and Parker drain tiles rest flush with the excavation bottom which positions the apertures therethrough in close proximity to the excavation bottom. Hreha and Parker thereby fail to address the prior art problems of aperture blockage and tile clogging caused by sediment gravitating through the leach field and accumulating at the excavation bottom.
Another problem with the prior art footing/foundation construction practice is the accurate placement of reinforcing bar within the footing/foundation. Reinforcing bar is specified in most construction projects to provide additional support to the foot/foundation. However, if the reinforcing bar is not properly positioned while the concrete is drying, much of the intended structural benefit may be sacrificed. As such, the site laborer must typically take measures to assure that the reinforcing bar does not fall to the excavation bottom or otherwise become misplaced as the concrete is poured between the forms.
The prior art reinforcing bar supports typically include either a number of simple blocks upon which the bar lays atop or a rather elaborate chair construction (i.e. the bar chair described in U.S. Pat. No. 4,060,954). The blocks, while inexpensive, are susceptible to adjustment during the concrete pouring stage which may lead to the reinforcing bar falling to the excavation bottom at one or more locations. The bar chairs, while more stable than the above-described blocks, may also adjust during the concrete pouring stage and are considerably more expensive thereby increasing the total cost of the construction project.
The present invention overcomes the foregoing problems by providing a footing/foundation form with an integral drain having two substantially parallel spaced apart, serpentuitous walls, each wall including a plurality of hollow tubes elevated "to grade" above an excavation bottom by a stake and clip mechanism with gravel filled between the elevated tubes and the excavation bottom. The tubes are connected end-to-end and preferably include a plurality of holes to enable water accumulating adjacent the footing/foundation to drain into a sewer, dry well, or sump pump. However, unlike the prior art forms having integral drainage means, the tubes of the present invention are preferably standard 10-foot PVC tubes available at many hardware and construction stores or are easily adapted from commonly available PVC tubes. The stakes are preferably pieces of reinforcing bar (or other steel rods which are readily available) and the clips, while quite effective, are inexpensively manufactured. As such, the present invention provides a footing/foundation form with integral drainage without the necessity of expensive custom molded materials which escalated the cost associated with the prior art techniques. Further, adjusting the depth (height) of the form is a simple matter of adjusting the tube, stake, and clip arrangement and adjusting the quantity of gravel placed therearound accordingly. Thus, the present invention accommodates a variety of footing/foundation parameters without the costly necessity of carrying an inventory of various supplemental solid plank sizes/shapes as with the prior art techniques.
In addition to the material cost savings, the present invention requires virtually no manual attention after the footing/foundation hardens which translates into significant labor cost savings. The gravel leach field of the present invention is intentionally created before the footing/foundation concrete is poured. In fact, the gravel is part of the concrete engaging section of the form. Because the gravel leach field is filled before the footing/foundation is poured, the possibility of backfill and/or debris accumulating around the excavation perimeter while the concrete is setting is greatly minimized. This eliminates the labor intensive necessity in the prior art to retrench the excavation perimeter after the footing/foundation hardens, which reduces labor costs. The present invention also reduces the chance for injury associated with human activity within an unshored trench and minimizes the likelihood of OSHA fines for noncompliance with its trench regulations.
Further, positioning the fluid conduit (the tubes) in spaced relation to the excavation bottom, provides several significant advantages over the prior art techniques. Because the conduit does not rest flush with the excavation bottom, the risk of silt and/or sediment (which accumulates at the excavation bottom over time) blocking the tube holes is greatly minimized. The likelihood of the tubes clogging over time is also reduced because the preferred embodiment provides several of the tube holes below the central horizontal plane of the tubes (and most preferably includes at least one hole facing substantially downward) which allows any silt and/or sediment which happens to enter the tube to gravity flow therefrom.
A cross-over pipe may also be added between the walls providing fluid communication therebetween, such that fluid within a clogged tube section in one wall may effectively drain via the cross-over pipe. Moreover, the cross-over pipes may be constructed to support a hook of various lengths therebelow. The hooks are inexpensive and will securely support reinforcing bar a desired distance above the excavation bottom, thereby addressing the prior art problems of securely and cost effectively supporting rebar within the foot/foundation.